I mean, within MS promotions happen all the time. Not that it's particularly easy, you have to demonstrate something over all the other smart people around you, but it definitely happens, it's encouraged and managers who have staff successfully promoted are rewarded for career development and staff retention. Admittedly, past a certain point, getting promoted puts a bit of a target on your back as expectations are higher, and those that don't exceed expectations don't tend to stay employed for long, but it certainly happens and if you don't have career opportunities for skilled workers in demand, they're going to go elsewhere...